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RobB

Simplest Standalone MSP430G2553 with USB-Serial?

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I've had some ebay FTDI chips before, there is a large market in chinese factories faking them, none have lasted more than 2 weeks in my possession before failing

=:-o

 

I guess I can't just chalk that up to you accidentally hitting them with a sledgehammer or something? :-(

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The FTDI is capable of jitter free operation at 3,000,000 / N bps. It can use fractional division for operation at more bit rates, but that causes some jitter, so I don't recommend it. It has no special knowledge of 'standard' bit rates like some other chips - it is a simple divider.

 

So the highest reliable bit rates for the FTDI chips are 1.5M, 1M, 750k, 600k, 500k, etc...

 

post-26480-0-69824400-1407407314_thumb.jpg

 

PL2303HXD can operate at 383385600 / ((4 ^ S) * D) bps, with S from 0 to 7 and D from 1 to 511, so it have finest resolution and highest max rate (12 Mbps) AFAIK than any bridge chip. Unfortunately, in bridge cables it is usually pared with low rate MAX323 chip and crippled to 2 Mbps or less. Of course that I completely dislike costumer support for PL2303HXD special baud rate.

 

For me 1 Mbps (or little more) offered by other chips is not enough.

 

I agree that Prolific have (or had) worst drivers, but I am using PL2303HXD on WinXP SP2 for years, on high rates, without problems.

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I personally prefer these FTDI cables for development, they are shipped with a 1x6 0.1" female header connector. You can use these even for breadboard setups. Because of the connector it's no problem to reuse the cable in other projects after development.

These are the ones I use too, specifically TTL-232R-3V3 which I have never had any issues with. Seems quite happy to take 5v input and other 5v devices are perfectly happy to run on the 3.3v output. Only thing to watch for with using it on a 3.3v system is that the VCC connector is USB voltage so 5v rather than a regulated 3.3v, easy enough to deal with (I have seen a 3rd variant of this type cable which does have a regulated 3.3v output but it isnt listed on there).

At full retail price they aren't always cheap but to me to have a quality cable which always works without fail is worth the

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Thanks for all of the very specific suggestions.  I guess I'm setting off on the same, sad road of disappointment with cheap alternatives.  I'll let you know how my ebay bridge works.

 

Has anyone tried a particular CH340 solution with good or bad results they want to share?  I think having these experiences all gathered in one place could be really helpful for those of us who are trying to navigate the options!

 

--Rob

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I have a few usb2serial cables based on the PL-2303X that is not supported anymore since windows 8 (you can actually install windows 7 drivers to make them work but it's a hassle). Never had a problem with these cables.

Seems like other chips than PL-2303HXA and PL-2303X should have working drivers.

 

I also tried high speed serial transfers with a stellaris launchpad once, I don't remember when it stopped being reliable but It could go up to a few Mbps (testing wasn't really scientific, the launchpad was just sending the ascii table over and over and I looked at some strange or out of place characters in the output).

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Just an update on my G2553-only logic analyzer that kicked this thread off: it managed to help me debug my I2C communications problem.  I was really in the dark as I had one uC as the master and another uC as the slave and no communication was happening.  So without the logic analyzer I didn't know where to start.  But with it I could see that the address was successfully being communicated by the master but there was no ACK from the slave.  So I focused in on the slave..... ARGH!  Forgot to enable interrupts!!!  How embarrassing...  But the logic analyzer did great!

 

Thanks for all of your help on getting it off the Launchpad and on to its own USB/UART bridge.  I'll keep you posted.

Rob

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I personally prefer these FTDI cables for development, they are shipped with a 1x6 0.1" female header connector. You can use these even for breadboard setups. Because of the connector it's no problem to reuse the cable in other projects after development.

 

+1

 

I spent about a week doing some tests with an 8051 and using that cable to upload firmware at 52,083 bps. The firmware verified correctly every time. For another project I've been working on for the last two months I've been using 500,000 and 1,000,000 bps without any problems.

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